'\" te
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.TH SYSBUS 5 "December 28, 2020"
.SH NAME
sysbus, isa \- device tree properties for ISA bus device drivers
.SH DESCRIPTION
Solaris for x86 supports the \fBISA\fR bus as the system bus. Drivers for
devices on this bus use the device tree built by the booting system to
retrieve the necessary system resources used by the driver. These resources
include device I/O port addresses, any interrupt capabilities that the device
can have, any DMA channels it can require, and any memory-mapped addresses it
can occupy.
.sp
.LP
Configuration files for \fBISA\fR device drivers are only necessary to describe
properties used by a particular driver that are not part of the standard
properties found in the device tree. See \fBdriver.conf\fR(5) for further
details of configuration file syntax.
.sp
.LP
The \fBISA\fR nexus drivers all belong to class \fBsysbus\fR. All bus drivers
of class \fBsysbus\fR recognize the following properties:
.sp
.ne 2
.na
\fB\fBinterrupts\fR\fR
.ad
.RS 16n
An arbitrary-length array where each element of the array represents a hardware
interrupt (IRQ) that is used by the device.  In general, this array only has
one entry unless a particular device uses more than one IRQ.
.sp
Solaris defaults all \fBISA\fR interrupts to IPL 5.  This interrupt priority
can be overridden by placing an \fBinterrupt-priorities\fR property in a .conf
file for the driver. Each entry in the array of integers for the
\fBinterrupt-priorities\fR property is matched one-to-one with the elements in
the \fBinterrupts\fR property to specify the \fBIPL\fR value that is used by
the system for this interrupt in this driver. This is the priority that this
device's interrupt handler receives relative to the interrupt handlers of other
drivers.  The priority is an integer from \fB1\fR to \fB16\fR. Generally,
disks are assigned a priority of \fB5\fR, while mice and printers are lower,
and serial communication devices are higher, typically \fB7\fR. \fB10\fR is
reserved by the system and must not be used.  Priorities \fB11\fR and greater
are high level priorities and are generally not recommended (see
\fBddi_intr_hilevel\fR(9F)).
.sp
The driver can refer to the elements of this array by index using
\fBddi_add_intr\fR(9F). The index into the array is passed as the
\fIinumber\fR argument of \fBddi_add_intr()\fR.
.sp
Only devices that generate interrupts have an \fBinterrupts\fR property.
.RE

.sp
.ne 2
.na
\fB\fBreg\fR\fR
.ad
.RS 16n
An arbitrary-length array where each element of the array consists of a 3-tuple
of integers.  Each array element describes a contiguous memory address range
associated with the device on the bus.
.sp
The first integer of the tuple specifies the memory type, \fB0\fR specifies a
memory range and \fB1\fR specifies an I/O range. The second integer specifies
the base address of the memory range. The third integer of each 3-tuple
specifies the size, in bytes, of the mappable region.
.sp
The driver can refer to the elements of this array by index, and construct
kernel mappings to these addresses using \fBddi_map_regs\fR(9F). The index into
the array is passed as the \fIrnumber\fR argument of \fBddi_map_regs()\fR.
.sp
All \fBsysbus\fR devices have \fBreg\fR properties.  The first tuple of this
property is used to construct the address part of the device name under
\fB/devices\fR. In the case of \fBPlug and Play ISA\fR devices, the first tuple
is a special tuple that does not denote a memory range, but is used by the
system only to create the address part of the device name.  This special tuple
can be recognized by determining if the top bit of the first integer is set to
a one.
.sp
The order of the tuples in the reg property is determined by the boot system
probe code and depends on the characteristics of each particular device.
However, the reg property maintains the same order of entries from system boot
to system boot.  The recommended way to determine the reg property for a
particular device is to use the \fBprtconf\fR(8) command after installing the
particular device.  The output of the \fBprtconf\fR command can be examined to
determine the reg property for any installed device.
.sp
You can use the \fBddi_get*\fR and \fBddi_put*\fR family of functions to access
register space from a high-level interrupt context.
.RE

.sp
.ne 2
.na
\fB\fBdma-channels\fR\fR
.ad
.RS 16n
A list of integers that specifies the DMA channels used by this device. Only
devices that use DMA channels have a \fBdma-channels\fR property.
.RE

.SH ATTRIBUTES
See \fBattributes\fR(7) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
Architecture	x86
.TE

.SH SEE ALSO
.BR driver.conf (5),
.BR scsi (5),
.BR attributes (7),
.BR prtconf (8),
.BR ddi_add_intr (9F),
.BR ddi_intr_hilevel (9F),
.BR ddi_map_regs (9F),
.BR ddi_prop_op (9F)
.sp
.LP
\fIWriting Device Drivers\fR
